Mitochondrial cardiomyopathy--case report

A male infant developed progressive neuromuscular disease, hypertrophic cardiomyopathy and brain atrophy since the birth. Increased level of lactate with increased lactate/pyruvate ratio suggested a disturbance in the mitochondrial energy metabolism. The activities of respiratory chain complexes III, IV and II + III, of pyruvate dehydrogenase complex and of citrate synthase in isolated muscle mitochondria were low in comparison with controls, with parallel decrease in the content of protein amount of respiratory chain complexes III and IV. No large scale deletions of mitochondrial DNA (mtDNA) and mtDNA point mutations A3243G, A8344G or T8993G indicating syndromes MELAS, MERRF or NARP were detected. The boy died at the age of 7 weeks. The autopsy revealed typical changes of mitochondrial cardiomyopathy-marked myocardial hypertrophy with muscle pallor, histological finding of diffuse fine granularity of the cytoplasm in the perinuclear regions, and ultrastructural findings of mitochondrial hyperplasia, enlargement (megamitochondria) and abnormal shape.

[Lysosomal sphingomyelinase deficiency: spectrum of phenotypes in Czech and Slovak patients]

BACKGROUND

We present a series of 25 patients (from 21 families) with deficiency of lysosomal sphingomyelinase (acid sphingomyelinase, ASM), diagnosed during the last 30 years.

METHODS AND RESULTS

Diagnosis was established by finding specific sphingomyelin storage pattern in bone marrow histiocytes and in some bioptical and postmortem tissues (presence of sphingomyelin liquid crystals) and finally by proving ASM deficiency in white blood cells and in cultured fibroblasts. Range of clinical manifestations of our patients notably exceeded the the known main (A,B) phenotypes described so far. In the group of type A patients (clinically overt neurovisceral symptomatology) there was significant tendency to prolonged course. Classical fulminant course with death between 5 to 45 months of age was seen only in a subgroup of 5 patients. In other type A patients (n = 8) the course was prolonged attaining 5 years of age, the end of the first (8, and 9 years), second (14, 17 years), third (22 years), fourth (32 years) and fifth decades (41 years). Three of these patients (aged 5, 22 and 41 years) are living. The series of patients with dominant visceral involvement (n = 12) consisted of three phenotypically different subgroups. One with chronic purely visceral affection and prolonged course (n = 4) corresponding to the classical type B, the second with chronic course and largely subclinical neurological affection (n = 4) and the third with accelerated fatal visceral affection (death in age range 31 months-9 years) without (n = 1) or with clinically minor signs of brain damage (n = 3).

CONCLUSIONS

Study of the presented series of ASM deficient patients disclosed remarkable phenotypical variability. Two main factors seem to be responsible. Variability in the storage intensity in the two main tissue compartments (neuronal and visceral), and the absence of proportionality in their affection in some instances. The described phenotype variability enlarges significantly the known spectrum of phenotypes in ASM deficiency.

[Metabolic complications and neurologic manifestations of vitamin B12 deficiency in children of vegetarian mothers]

BACKGROUND

Serious hematological, metabolic and neurological complications owing to the nutritional deficiency of vitamin B12 may occur in infants of mothers on a strict vegetarian diet.

METHODS AND RESULTS

The mother of the first child was a strict vegetarian. She had an elevated urinary methylmalonic acid level and a low concentration of serum vitamin B12. Her 13-month-old daughter was exclusively breast-fed until the age of 9 month and then she was fed only vegetables. Physical examination revealed psychomotoric retardation, apathy, muscular hypotonia, abnormal movements and failure to thrive. Laboratory analysis showed a megaloblastic anaemia, a low level of vitamin B12 and methylmalonic aciduria. MRI of the brain revealed diffuse frontotemporoparietal atrophy and retardation of myelination. After treatment with vitamin B12 supplements, abnormal movements disappeared and development improved, but a mild generalised hypotonia continued. A cranial MRI 9 months after treatment still showed signs of retardation of myelination. The second patient, an 8 month-old male, son of a strict vegetarian mother too, was referred for investigation of psychomotoric retardation, hypotonia, dyskinesia, failure to thrive and microcephaly. He was breast-fed and from 6 month of age he had also received fruit juices. Laboratory analysis revealed megaloblastic anaemia, high methylmalonic aciduria and homocystinuria. The patient's and his mother's serum level of vitamin B12 were low. After treatment with vitamin B12 supplements, biochemical and metabolic markers of disease were normal but there continued a generalised hypotonia, microcephaly and language delay.

CONCLUSION

Our observations emphasize the health complications of nutritional cobalamine deficiency and a requirement of clinical, biochemical and metabolic monitoring in infants within strict vegetarian families.

Socialization of children's emotion regulation in mother-child dyads: a developmental psychopathology perspective

This study investigated the socialization of children's emotion regulation in 25 physically maltreating and 25 nonmaltreating mother-child dyads. Maltreating mothers and their 6- to 12-year-old children were recruited from two parenting programs affiliated with Children's Protective Services with a control group matched on race, SES, child gender, and child age. Children and their mothers were interviewed individually about their (a) management of emotional expression. (b) strategies for coping with emotional arousal, and (c) anticipated consequences following emotional displays. Compared to controls, maltreated children expected less maternal support in response to their emotional displays, reported being less likely to display emotions to their mothers, and generated fewer effective coping strategies for anger. Maltreating mothers indicated less understanding of children's emotional displays and fewer effective strategies for helping children to cope with emotionally arousing situations than nonmaltreating mothers. Further, findings indicated that maternal socialization practices (e.g., providing support in response to children's emotional display, generating effective coping strategies for their child) mediate the relation between child maltreatment and children's regulation of emotional expression and emotional arousal. These findings suggest that children's emotion regulation strategies are influenced by their relationship with their social environment (e.g.. physically maltreating, nonmaltreating) and that the experience of a physically maltreating relationship may interfere with children's emotional development.

Novel mutations in a boy with dihydrolipoamide dehydrogenase deficiency

BACKGROUND

Dihydrolipoamide dehydrogenase (DLD) deficiency is a rare cause of primary lactic acidosis in infancy.

MATERIAL AND METHODS

This article presents the results of biochemical and molecular analyses and metabolic response to treatment procedures in a 10-week old boy presenting with vomiting, progressive hypotonia, lactic acidosis (pH 7.04; BE - 20; B-lactate 6.6 mmol/l, controls <2.1; CSF-lactate 4.8 mmol/l, controls <2.0), increased levels of branched chain amino acids in blood, and increased urinary excretion of branched chain oxo-acids due to DLD deficiency.

RESULTS

DLD activity was less than 5% of control values in lymphocytes, muscle mitochondria and fibroblasts. Western blot analysis in muscle tissue showed a decrease in the quantity of DLD protein to 40% in comparison to control. A high-fat, low-protein diet supplemented with MCT oils and sodium dichloroacetate resulted in normalization of lactate, amino acids and organic acids in body fluids, but there was no improvement in psychomotor development. Novel heterozygous mutations were found in the DLD gene: A1081G and G1123A. Both mutations affect the same region of the binding site for FAD. The G1123A mutation, resulting in the substitution of Glu 375 > Lys, breaks down the possible interaction of glutamic acid with neighboring lysine and causes electrostatic and steric repulsion, which is likely to destabilize structure in this part of the protein. In case of the A1081G mutation, resulting in substitution of Met 361 > Val, no important intermolecular interactions are broken and the reason for destabilization of the protein is not as clear.

CONCLUSIONS

The prognosis for children with DLD deficiency is unfavorable, although long-term normalization of most metabolites in body fluids may be achieved with the proper diet and the administration of sodium dichloroacetate.

[Analysis of the most frequent mutations in girls with Rett syndrome]

BACKGROUND

Rett syndrome is an X-linked dominant neurodevelopmental disorder affecting 1 from 10,000 to 15,000 females worldwide. The responsible gene, encoding methyl-CpG binding protein 2 was recently identified. Methyl-CpG binding protein 2 is thought to act as a global transcriptional repressor. In the methyl-CpG binding protein 2 gene are known 5 prevalent mutations that cause Rett syndrome. Four of them are detectable by restriction analysis. In this study we present the results of the molecular study of four prevalent mutations in the gene for methyl-CpG binding protein 2 in Czech and Slovak patients with Rett syndrome.

METHODS AND RESULTS

22 females with Rett syndrome were investigated by methods of molecular biology. Restriction analysis and direct sequencing of PCR products revealed in methyl-CpG binding protein 2 gene 3 different mutations (T158M, R168X, R270X) in six unrelated patients with Rett syndrome. Mutation R306C, frequent in Great Britain and Sweden, was not detected in our group of patients with Rett syndrome.

CONCLUSIONS

The diagnosis of Rett syndrome and genetic counselling in affected families should go out from the close cooperation of the pediatric, neurologic, and genetic departments with the specialized laboratories dealing with the molecular biological diagnosis.

Pulmonary storage with emphysema as a sign of Niemann-Pick type C2 disease (second complementation group). Report of a case

A case is described of Niemann-Pick type C2 disease presenting an infantile pneumopathic phenotype known to occur in this recently established, second, minor complementation group of Niemann-Pick type C (NPC) disease. However, the pulmonary involvement was unique, being dominated, in addition to the usual storage macrophage infiltration of the alveolar and septal compartments, by irregular emphysema attributed to storage cell migration into the bronchiolar lumen. The latter modified considerably the X-ray findings and hindered the initial clinical diagnosis. Otherwise, the storage phenotype, including the range of stored lipids, storage distribution, and cell and organ pathology, was found to be identical to that in the whole Niemann-Pick type C disease group dominated by NPC1. The biochemical findings (cholesterol esterification level) corresponded to the classical biochemical phenotype. Emphysema should thus be considered as a variant of the pulmonary NPC2 storage process, governed most probably by an epigenetic mechanism responsible for storage macrophage migration into the bronchiolar compartment.

A novel mutation in SURF1 causes skipping of exon 8 in a patient with cytochrome c oxidase-deficient leigh syndrome and hypertrichosis

Leigh syndrome is a rare pediatric neurodegenerative disorder attributed to impaired mitochondrial energy metabolism. Mutations in SURF1 have been described in several patients with Leigh syndrome associated with cytochrome c oxidase deficiency. We report a new 18-bp deletion (821del18), spanning the splice donor junction of exon 8 of SURF1, in an infant presenting with cytochrome c oxidase-deficient Leigh syndrome and hypertrichosis. cDNA sequencing demonstrated that this deletion results in a messenger lacking exon 8. RT-PCR experiments suggested a rapid degradation of the aberrant mRNA species from the 5'-end.

[Congenital aplastic anemia caused by parvovirus B19 infection]

Human parvovirus B19 causes the fifth disease (erythema infectiosum) in childhood. Intrauterine infection by parvovirus in immunocompromised fetus can lead to the severe congenital aplastic anemia. Here we report the case of 2.5-year-old girl with congenital infection with parvovirus B19. The girl was born as a pre-term baby with hydrops, congenital aplastic anemia, and low level of immunoglobulins IgG and IgM. She depended on the repeated blood transfusions and she did not respond to erythropoietin therapy. The parvovirus B19 infection in bone marrow was detected by polymerase chain reaction and its therapy started with intravenous administration of immunoglobulins. Hemoglobin reached normal level one year later, but low levels of parvovirus B19 were detectable for another 6 months. Immunoglobulin treatment was finished when the virus could not be detected in the circulation. However, one-month later parvovirus B19 DNA was detected again. The two months course of immunoglobulin treatment was repeated, and the DNA analysis of blood cells for parvovirus B19 has been negative since then. Five months after the final withdrawal of the immunoglobulin therapy the girl is in a good shape and all lab tests, except for the decreased levels of IgM, are within the normal range. The PCR monitoring of the presence of parvovirus B19 DNA in blood and bone marrow cells during and after the treatment of congenital aplastic anemia caused by parvovirus B19 chronic infection becomes the necessity for the rational therapy.

Magneto infrared absorption in high electron density GaAs quantum wells

Magneto infrared absorption measurements have been performed in a highly doped GaAs quantum well which has been lifted off and bonded to a silicon substrate, in order to study the resonant polaron interaction. It is found that the pinning of the cyclotron energy occurs at an energy close to that of the transverse optical phonon of GaAs. This unexpected result is explained by a model taking into account the full dielectric constant of the quantum well.

[Clinical picture of homocystinuria with cystathionine beta-synthase deficiency in 19 Czech and Slovak patients]

BACKGROUND

Homocystinuria due to cystathionine beta-synthase deficiency is an autosomal recessive disorder of methionine metabolism. It manifests with vascular, central nervous system and connective tissue disturbances, and phenotypically resembles Marfan's syndrome. We analysed the clinical course of homocystinuria in Czech and Slovak patients.

METHODS AND RESULTS

The group of homocystinuric patients consisted of 19 individuals (12 males and 7 females) aged 5-32 years (average age 18 years), who were diagnosed between 1980 and 1999. The overall incidence of homocystinuria in the Czech and Slovak Republics was 1:287,000. The proportion of pyridoxine-responsive patients was 47%. The average follow-up period was 10 years (range 1 month to 19 years). The prevalence of the individual signs in the group was as follows: lens dislocation--95% of patients, progressive myopia--79%, marfanoid habitus--74%, kyfoscoliosis--68%, osteoporosis--63%, psychomotor retardation--58%, other neurologic symptomatology--58% and tromboembolism--21%. The average delay between the first sign of the disease and the time when the diagnosis was made was 4 years (range 1 to 14 years). At the time of diagnosis the average levels of metabolites in plasma were as follows: total homocysteine 348 mumol/l (range 211-536), free homocystine 70 mumol/l (range 0-203) and methionine 359 mumol/l (range 75-937).

CONCLUSIONS

Both the clinical course of homocystinuria due to the cystathionine beta-synthase deficiency and its incidence in the Czech and Slovak Republics are similar to those in other populations. Since homocystinuria is a treatable disease, it should be included in the differential diagnosis of Marfan's syndrome, tromboembolism and severe psychomotor retardation.

Emotion management skills in sexually maltreated and nonmaltreated girls: a developmental psychopathology perspective

Research has demonstrated that children who experience familial sexual maltreatment are at risk for developing psychological difficulties characterized by emotional and behavioral dysregulation. Surprisingly, however, little attention has been directed toward identifying processes in emotional development that differ in maltreated and nonmaltreated children. From a developmental psychopathology perspective, the present study examined emotion management skills (i.e., emotional understanding, emotion regulation) in 21 sexually maltreated girls and their nonmaltreated peers to determine how the experience of sexual maltreatment may interfere with normative emotional development. Findings indicated that sexually maltreated girls, in comparison to their nonmaltreated peers, demonstrate lower emotional understanding and decreased ability to regulate their emotions in accordance with cultural expectations. Further, maltreated girls expected less emotional support and more relational conflict from parents in response to sadness displays and from parents and peers in response to anger displays. These findings will be discussed from the functionalist approach to emotional development, emphasizing the importance of social context (e.g., maltreating, nonmaltreating) in the development of children's emotion management skills.

New insights in cardiac structural changes in patients with Fabry's disease

BACKGROUND

Fabry's disease is an X-linked recessive genetic deficiency of the enzyme alpha-galactosidase leading to the pathologic intracellular deposition of neutral glycosphingolipids. Although cardiac involvement is frequent, there is controversy regarding the character of the associated left ventricular (LV) changes and the severity of valvular involvement.

METHODS

Clinical evaluation (disease severity scaling, laboratory tests, and echocardiography) was performed in 13 hemizygous men (mean age 39 +/- 10 years) and 17 heterozygous women (mean age 35 +/- 19 years).

RESULTS

LV hypertrophy (LVH) was frequent in subjects older than 30 years, more often in men (61%) than in women (18%, P <.001). The degree of LVH was independently associated with age and the logarithm of alpha-galactosidase activity (r(2) = 0.70, P <.001). The predominant LV geometric patterns were concentric LVH and remodeling, both present in 11 subjects (36%). Three patients had an asymmetric septal hypertrophy mimicking hypertrophic cardiomyopathy. In most subjects with LVH, the systolic function was normal and severe diastolic dysfunction (restrictive pattern) was not noted. Minor structural abnormalities of the mitral valve were found in 17 subjects (57%). The aortic valve was affected in 14 patients (47%). Valvular abnormalities were frequently accompanied by regurgitation of minor to mild degree. The presence of LVH or valvular changes was associated with increased disease severity.

CONCLUSIONS

Echocardiographically detectable cardiac involvement is frequent with Fabry's disease, particularly in older subjects, and more pronounced in affected hemizygous men than in heterozygous women. LVH is frequently observed but usually not associated with significant systolic or restrictive diastolic dysfunction. Concentric LVH and remodeling appear to be the major manifestations of LV structural alteration. The frequently noted valvular abnormalities were not associated with a significant degree of regurgitation. Valvular and especially LV structural changes may serve as a useful marker of disease severity.

[Prenatal diagnosis in families with cytochrome C oxidase disorder]

OBJECTIVE

Cytochrome c oxidase (COX) deficiency presents with severe impairment of brain, muscle or heart. Prenatal diagnosis in affected families is difficult because the disease may be caused by mutations in nuclear or mtDNA. This study shows the results of prenatal diagnosis in two families where the first child died because of a generalised COX defect. In both cases the low activity of COX was accompanied by a low content of the enzyme.

SUBJECTS

In the first family the amniocentesis was performed during the second pregnancy and cultured amniocytes showed a marked decrease of COX activity and ATP production. Based on decision of the parents the pregnancy was terminated. Analysis of the foetal tissues confirmed a generalised COX defect. In the second family the nuclear origin of the COX defect was found using transmitochondrial cybrids derived from COX-deficient fibroblasts of the affected child. In the successive pregnancy with dizygotic twins a combined amniocentesis and chorionic villi biopsy has been performed. Prenatal diagnosis was based in both foetuses on three independent approaches. COX activity, the ATP production and protein content of COX complex was measured in cultivated foetal cells. The results of all investigations excluded a putative COX defect and both children are healthy at the age of 2 and half years.

CONCLUSION

Prenatal diagnosis of COX disorders is available in families with the generalised form of the disease based on a nuclear origin of COX deficiency. Three independent approaches to characterise COX at a functional, enzymatic and protein level may be used.

Bone mineral density in patients with phenylketonuria

Dual energy X-ray absorptiometry was performed in 44 patients with phenylketonuria (PKU) aged 6-29 y. The phenylalanine-restricted diet was based on a low-protein diet in combination with phenylalanine-free amino acid mixtures and phenylalanine-low casein hydrolysate in 32 patients. The 10 oldest patients were supplemented only with casein hydrolysate, and the youngest child received only the amino acid mixture. One patient has recently come off the diet. Bone mineral density (BMD) of the lumbar spine and total BMD were measured and expressed as Z-score, i.e. the difference between the BMD of the patient and the average BMD of sex- and age-matched controls divided by the standard deviation of the control group. Normal BMD was found in 24 (54%) patients. Lumbar spine BMD was decreased in 20 patients and total BMD was decreased in 14 patients. Z-scores of -1to 2.5 were found in 14 patients (32%) and Z-scores of <-2.5 in 6 patients (14%). No significant correlation was found between total or lumbar spine BMD and daily intake of phenylalanine from natural sources in the low-protein diet or the amount of phenylalanine-free amino acid mixtures per kg of body weight. A significant negative correlation was observed between both total and lumbar spine BMD Z-scores and the amount of casein hydrolysate supplementation per kg of body weight (r = - 0.45; y = 0.07 - 0.69x; p < 0.01). Long-lasting dietary restriction in patients with PKU may increase the risk of late complications of dietary therapy, such as osteoporosis or trace element deficiency. O Bone mineral density, osteoporosis, phenylalanine-low diet, phenylketonuria

Incorporating a developmental perspective in doctoral training: survey of clinical child psychology training programs and introduction to the special section

Examined the degree to which clinical child programs incorporate and integrate developmental theory into their training, and introduced the contributions of 6 leaders in the field to this special section. Fifty-one clinical child doctoral programs responded to the survey. Results indicate that 3 types of training programs are operating: (a) child emphasis (n = 7), which do not have a formal clinical child training program but do have a faculty member who has child research interests; (b) clinical child (n = 37), which have a group of faculty members with specific child research and clinical interests and a formalized program of study; and (c) developmental-clinical programs (n = 7), which are similar to clinical child programs but require a substantive amount of developmental psychology course work and endorse a developmental psychopathology perspective. Findings reveal that clinical child programs have become increasingly differentiated and specialized over the past 20 years, but, with the exception of developmental-clinical programs, most programs are still neglecting to incorporate developmental theory into training. This issue, as well as concerns about the future direction of clinical child doctoral training is addressed in this special section on the Importance of Incorporating Developmental Theory Into Clinical Child Training.

[Lysosomal acid lipase deficiency. Overview of Czech patients]

Lysosomal lipase deficiency is a hereditary autosomal recessive enzymopathy leading to lysosomal storage of triacylglycerols (TAG) and cholesterol esters (CE). In particular cells with a permanently high receptor-mediated LDL endocytosis are affected (liver, kidneys). There are two basic phenotypes. The fatal infantile phenotype (Wolman's disease) with generalized storage of both types of apolar lipids. This form was diagnosed in this country only once. The opposite is the protracted, oligosymptomatic form encountered in all age groups. It is characterized by the storage of CE (which gave this entity the name of cholesteryl storage disease--CESD). Its main sign is affection of the liver (hepatomegaly, hepatopathy), which in some instances may lead to organ failure, directly or after cirrhotic transformation. Furthermore there is permanent hypercholesterolaemia (high LDL cholesterol) due to increased VLDL synthesis by hepatocytes, low HDL cholesterol and variably raised TAG. This constellation of blood lipids is a risk factor for the development of atherosclerosis. In the course of 25 years in the Czech Republic 13 cases of CESD were diagnosed in 11 families. Ten of these cases were characterized by clinically manifest hepatopathy with hepatomegaly, detected incidentally during medical examinations (at the age of 2-14 years). In three adult patients with permanent hypercholesterolaemia the storage process was subclinical and the diagnosis was established quite incidentally by examination of non-specific secondary and tertiary manifestations of the disease. The diagnosis was established in all cases of CESD at the tissue level (liver biopsy), at the biochemical (acid lipase deficiency) and molecular genetic level (mutation in enzyme locus). In all instances mutation of G934A was found leading to reduction and loss of the eighth exon. This mutation was present in five patients in a homozygous state. Six mutations were heterozygous. In one instance for technical reasons only one allele was analyzed. In three instances a point "missense" mutation was found: T323A (Trp74Arg), T4(75)A (Asp124Glu), A210T (Asp36Gl), in one instance a "nonsense" mutation: C233T (Arg44-stop) and twice a deletion mutation delta C673-5 and delta G1068-8 leading to impairment of the reading frame and to premature stop of the codon.

[Postmortem diagnosis of Fabry disease in a female heterozygote leading to the detection of undiagnosed manifest disease in the family]

The authors detected on necropsy in a 63-year-old woman with the clinical diagnosis of hypertension, atherosclerosis of the coronary and peripheral arteries, thromboembolism into the cerebral circulation and impaired cardiac conductivity lysosomal storage identified by histochemical and electronoptic analyses along with lipid chromatography as Fabry's disease. The stored lipids were neutral glycosphingolipids of the globo series globotriaosylceramide) and of the gala- series (galabiosylceramide) which accumulated as a result of deficient activity of the degrading enzyme alpha galactosidase A. Marked accumulation of these specific lipids was found in cardiomyocytes, in smooth muscles (of the media in arteries of the heart, kidneys, liver, spleen, lungs) in podocytes and mesangial cells of renal glomeruli, in epithelia of Henle's loop and in the distal tubules. In the vascular endothelium the storage was at the borderline of detectability. Accumulation did not lead to detectable organ disorders with the exception of the heart where it participated, no doubt, significantly in the cardiocyte hypertrophy. Examination of relatives revealed in the proband's son (age 41 years) a combination of renal, cardiac and skin changes typical for Fabry's disease which, however was not clinically diagnosed. The diagnosis was confirmed by proving of alpha-galactosidase A deficiency in the peripheral leucocytes and point mutation L293X in the VIth exon of the appropriate gene. In a granddaughter (age 15 years) biochemical and molecular genetic methods revealed the heterozygous state of Fabry's disease in preclinical stage.

[Leber's hereditary optic nerve neuropathy]

The authors present a case report of 26 years old man with bilateral optic nerve neuropathy. Detection of heteroplasmic mutation of mitochondrial DNA at G3460A site confirmed the suspicion on Lebers hereditary optic nerve neuropathy (LHON). Genetic and environmental factors of the disease and various accompanying neurologic and other symptoms, which can together with the optic nerve defect participate in the development of of the LOHN clinical pattern are discussed. (Ref. 12.)

[Leber's hereditary optic neuropathy]

BACKGROUND

Leber's hereditary neuropathy of the optic nerve (LHON) is manifested by bilateral affection of the eyes with acute or subacute loss of vision. The disease is caused by point mutations in the mitochondrial DNA (mtDNA) and is one of the most frequent mitochondrial diseases in the population. In patients with LHON 18 different point mutations in the mtDNA were described which correlate partly with the rate of progression of the disease and the severity and prognosis of the final affection of vision.

METHODS AND RESULTS

The submitted paper deals with the results of molecular genetic examinations in three families with clinical manifestations of LHON. In three patients in the first family a homoplasmic mutation of mtDNA G3460A was found. In the second family in a young man with severely impaired vision a heteroplasmic mutation G3460A was found associated with a higher ratio of mutated mtDNA molecules than in his mother who is clinically healthy. In the third family the presence of homoplasmic mutation of mtDNA in position G11778A was detected.

CONCLUSIONS

The diagnosis of LHON and genetic counselling in affected families should be based on close collaboration of ophthalmological and genetic departments with specialized laboratories engaged in molecular biological diagnosis of mitochondrial diseases.

A novel deficiency of mitochondrial ATPase of nuclear origin

We report a new type of fatal mitochondrial disorder caused by selective deficiency of mitochondrial ATP synthase (ATPase). A hypotrophic newborn from a consanguineous marriage presented severe lactic acidosis, cardiomegaly and hepatomegaly and died from heart failure after 2 days. The activity of oligomycin-sensitive ATPase was only 31-34% of the control, both in muscle and heart, but the activities of cytochrome c oxidase, citrate synthase and pyruvate dehydrogenase were normal. Electrophoretic and western blot analysis revealed selective reduction of ATPase complex but normal levels of the respiratory chain complexes I, III and IV. The same selective deficiency of ATPase was found in cultured skin fibroblasts which showed similar decreases in ATPase content, ATPase hydrolytic activity and level of substrate-dependent ATP synthesis (20-25, 18 and 29-33% of the control, respectively). Pulse-chase labelling of patient fibroblasts revealed low incorporation of [(35)S]methionine into assembled ATPase complexes, but increased incorporation into immunoprecipitated ATPase subunit beta, which had a very short half-life. In contrast, no difference was found in the size and subunit composition of the assembled and newly produced ATPase complex. Transmitochondrial cybrids prepared from enucleated fibroblasts of the patient and rho degrees cells derived from 143B. TK(-)human osteosarcoma cells fully restored the ATPase activity, ATP synthesis and ATPase content, when compared with control cybrids. Likewise, the pattern of [(35)S]methionine labelling of ATPase was found to be normal in patient cybrids. We conclude that the generalized deficiency of mitochondrial ATPase described is of nuclear origin and is caused by altered biosynthesis of the enzyme.

Defective kinetics of cytochrome c oxidase and alteration of mitochondrial membrane potential in fibroblasts and cytoplasmic hybrid cells with the mutation for myoclonus epilepsy with ragged-red fibres ('MERRF') at position 8344 nt

We have investigated pathogenic effects of the tRNA(Lys) A8344G mutation associated with the syndrome myoclonus epilepsy with ragged-red fibres (MERRF) by using fibroblasts and fibroblast-derived cytoplasmic hybrid cells harbouring different percentages of mutated mitochondrial DNA (mtDNA). The activity of cytochrome c oxidase (COX) in patient fibroblasts with 89% mutated mtDNA was decreased to 20% of the control levels. COX exhibited altered kinetics, with a decreased V(max) for both the low-affinity and high-affinity phases; however, the K(m) values were not significantly changed. The substrate-dependent synthesis of ATP was decreased to 50% of the control. Analysis of the mitochondrial membrane potential, DeltaPsi, in digitonin-treated cells with tetramethylrhodamine methyl ester (TMRM) with the use of flow cytometry showed a 80% decrease in DeltaPsi at state 4 and an increased sensitivity of DeltaPsi to an uncoupler in fibroblasts from the patient. The investigation of transmitochondrial cytoplasmic hybrid clones derived from the patient's fibroblasts enabled us to characterize the relationship between heteroplasmy of the MERRF mutation, COX activity and DeltaPsi. Within the range of 87-73% mutated mtDNA, COX activity was decreased to 5-35% and DeltaPsi was decreased to 6-78%. These results demonstrate that the MERRF mutation affects COX activity and DeltaPsi in different proportions with regard to mutation heteroplasmy and indicate that the biochemical manifestation of the MERRF mutation exerts a very steep threshold of DeltaPsi inhibition.

Emotional understanding: a comparison of physically maltreating and nonmaltreating mother-child dyads

Investigated emotional understanding in 22 physically maltreating mothers and their children and a matched control group to determine the ways in which a maltreating relationship may interfere with children's emotional development. Findings indicated that, when compared to controls, maltreating mothers were less likely to engage in discussion reflective of emotional understanding (e.g., causes and consequences of emotion) and maltreated children demonstrated lower levels of emotional understanding. Further, significant relations emerged between maternal behavior (e.g., discussion of emotion) and children's emotional understanding skills. Findings are discussed from the functionalist approach to emotional development, emphasizing the importance of social context in the development of children's emotional understanding skills. Potential clinical applications are also considered.

Combined adenine phosphoribosyltransferase and N-acetylgalactosamine-6-sulfate sulfatase deficiency

We describe a Czech patient with combined adenine phosphoribosyltransferase (APRT) deficiency (2,8-dihydroxyadenine urolithiasis) and N-acetylgalactosamine-6-sulfate sulfatase (GALNS) deficiency (mucopolysaccharidosis Type IVA, Morquio disease A). Adenine and its extremely insoluble derivative, 2,8-dihydroxyadenine, were identified in the urine, and APRT deficiency was confirmed in erythrocytes. There was excessive excretion of keratan sulfate in the urine, and GALNS deficiency was confirmed in leukocytes. GALNS and APRT are both located on chromosome 16q24.3, suggesting that the patient had a deletion involving both genes. PCR amplification of genomic DNA indicated that a novel junction was created by the fusion of sequences distal to GALNS exon 2 and proximal to APRT exon 3, and that the size of the deleted region was approximately 100 kb. The deletion breakpoints were localized within GALNS intron 2 and APRT intron 2. Several other genes, including the alpha subunit of cytochrome B (CYBA), which is deleted or mutated in the autosomal form of chronic granulomatous disease, are located in the 16q24.3 region, but PCR amplification showed that this gene was present in the proband. A patient with hemizygosity for GALNS deficiency and APRT deficiency has been reported from Japan recently. These findings indicate that: (i) APRT is located telomeric to GALNS; (ii) GALNS and APRT are transcribed in the same orientation (centromeric to telomeric); and (iii) combined APRT/GALNS deficiency may be more common than hitherto realized.